The peritoneal dialysis (PD) modality was introduced before Hemodialysis. However, because of the high infection rates associated with PD treatment, Hemodialysis has become the major modality used for life support of End-Stage-Renal-Failure. This is true for both chronic and acute patients.
Hemodialysis is a direct treatment of blood using an extracorporeal system with an artificial membrane (kidney). PD uses the principles of osmosis and diffusion across the peritoneal membrane to indirectly remove toxic waste and substances from the blood, thereby correcting certain electrolyte and fluid imbalances. By the nature of the operation, PD is a slower but more gentle dialysis technique. The extracorporeal hemodialysis is used more often when rapid and efficient dialysis is necessary because of excessive patient load and/or severe renal failure or drug intoxication.
Technically, hemodialysis is more demanding and restrictive for patients than PD. These along with other medical, economical and social reasons have resulted in steadily increasing use of the simpler PD.
As more attention is paid to PD, new technical improvements are also introduced. The current advances in PD have led to an increasing number of patients using PD at home. Some of these advances have introduced different PD techniques and others have helped to reduce the peritonitis (infection) rate. Peritonitis is by far the most serious complication limiting the growth of PD.
The automated PD techniques such as Intermittent Peritoneal Dialysis (IPD), and Continuous Cyclic Peritoneal Dialysis (CCPD) have proven to reduce the risk of peritonitis. However, since Continuous Ambulatory Peritoneal Dialysis (CAPD) is a simpler form of home PD treatment, the majority of PD patients are trained in this therapy.
With CAPD the patient manually performs four to six fluid exchanges per day using sterile packaged dialysate. Between exchanges the patient carries the dialysate the peritoneal cavity for four or more hours. Of all the PD techniques CAPD has the highest peritonitis rate. Repeated peritonitis may cause scarring of the peritoneal membrane and may reduce membrane permeability and hence dialysis efficiency. These may also lead to premature termination of PD therapy for the patient. Hence the severity and frequency of peritonitis have led to many technical advances and techniques all directed for use with CAPD.
The "povidone-iodine clamp" is supposed to prevent bacterial penetration through the catheter lumen. The "UV-XD Ultraviolet Germicidal System" is supposed to reduce bacterial counts during the bag exchange. The "Sterile Connection Device" provides sterile "heat-weld" between the patient line and dialysate solution bag. The "Peridex CAPD Filter Set" is meant to prevent bacteria from entering the peritoneal cavity.
Unfortunately, none of these special devices has proven capable of significantly reducing the peritonitis rate in any controlled studies, and the search has continued for a device or technique which will remove this impediment from the PD population.
The recent application of the "Y" tubing set has exhibited a major promise of peritonitis rate reduction in CAPD. However, the complexities and unrefined procedure of the "Y" set have not made "Y" set operation friendly to the patients. Hence, poor patient compliance, which leads to poor aseptic technique, has masked any great beneficial contribution of the "Y" set to reduction of the peritonitis rate.
Two recent developments of the "Y" set will be described subsequently in this disclosure, along with their shortcomings. This description will be made with reference to the drawings.